Locking users access to OneDrive for Business (O365)

Hi all,

I am running a O365 tenant consolidation exercise (comapny merger). Part of the work is to migrate the users' ODFB from source O365 tenant to destination O365 tenant. I am using SkySync for the capability to copy files and the migration is on-going for batches of users.

For users which I have done the migration, I need to ensure they do not continue to make changes to the source ODFB. This need to cover the following scenarios:

1. Owners of the ODFB cannot access (DONE, by revoking permission as site collection admin of their ODFB site)

2. Remove sharing permission given to other users

#2 is where I am stuck, as there's no options to remove all exsiting sharing hyperlinks for specific users. Option are avaialble to turn-off external sharing, but I need to also disable sharing to people within the organization.

Anyone have any ideas how to tackle this in an efficient manner?